The present invention is generally related to motor vehicle frames and more particularly to motor vehicle space frames constructed using hydroformed members.
Tubular hydroforming is increasingly used in vehicle frame construction because tubular hydroforming offers automobile manufacturers many commercial advantages. The use of tubular hydroforming enables manufacturers to better control frame stiffness, dimensional stability, fatigue in life, and vehicle crashworthiness over prior vehicle designs while reducing frame mass and cost. Hydroforming is a metal-forming process in which high-pressure fluid is used to outwardly expand a tubular metal blank into conformity with the surfaces of a die cavity of a die assembly to form an irregularly shaped tubular part. Hydroformed members can be provided with a wide range of geometries in comparison with other methods of forming parts. Each hydroformed frame member can be constructed to have a cross-sectional configuration that varies continuously along its length, to the configuration desired and each frame member can be constructed to curve or xe2x80x9cbendxe2x80x9d along its length to define different frame parts such as frame side rails and frame pillars.
Depending on specific circumstances, certain xe2x80x9csharpxe2x80x9d bends may not be advantageous or possible due to particular space constraints for certain motor vehicle designs. Space frames are cage-like structures on which other vehicle components, including the engine, drive train, suspension and the hang-on vehicle body parts, can be mounted. Tubular hydroformed space frames may be used in the construction of relatively large vehicles such as sports utility vehicles and larger sedans and trucks. In relatively larger frame vehicles, angular limitations on the construction on tubular hydroformed members generally pose few problems. However, the limited space available in some motor vehicles such as compact or other smaller frame cars can limit the use of hydroformed space frames therein. This is especially true when the motor vehicle has set interior and exterior configurations and the frame must be fit between the two.
There is a need for a vehicle space frame that can provide the benefits of tubular hydroformed construction for smaller frame vehicles with limited frame space.
To meet the needs expressed above, the present invention provides space frame for a motor vehicle that includes a pair of tubular, hydroformed longitudinally extending lower side rail members and a pair of tubular, hydroformed upper longitudinal members. Each of the upper longitudinal members includes a rear pillar-forming portion and a rail-forming portion, each of the pillar-forming portions being coupled to an end of a respective one of the lower side rail members and extending upwardly therefrom to define a rearward-most pillar of the motor vehicle and each of the rail-forming portions extending forwardly from the pillar-forming portion to define a roof support rail of the motor vehicle. The space frame further includes a pair of forward-most pillar assemblies, each of the pair of forward-most pillar assemblies being coupled to a respective one of the pair of lower side rail members and extending upwardly therefrom and being coupling with a respective one of the upper longitudinal members, and each of the forward-most pillar assemblies being formed from stamped sheet metal. A laterally extending connecting structure is mounted between the pair of lower side rail members, the connecting structure being constructed and arranged to hold the pair of lower side rail members in laterally spaced relation to one another.
The invention further provides space frame for a motor vehicle comprising a pair of tubular, hydroformed longitudinally extending lower side rail members and a pair of tubular hydroformed upper longitudinal members. Each of the upper longitudinal members includes a rear pillar-forming portion and a rail-forming portion, each pillar-forming portion being coupled to an end of a respective one of the lower side rail members and extending upwardly therefrom to define a rearward-most pillar of the motor vehicle and each of the rail-forming portions extending forwardly from the rear pillar-forming portion to define a roof support rail of the motor vehicle. The space frame further includes pair of pillar support structures, each pillar support structure being of stamped sheet metal construction and each being connected to a respective lower side rail member at the location to support a forward-most pillar structure. The space frame also includes a pair of forward-most pillar structures, each pillar structure being coupled at a lower end thereof to an associated pillar support structure and being coupled at an upper end thereof to an associated upper longitudinal member. A laterally extending connecting structure is mounted between the pair of lower side rail members, the connecting structure being constructed and arranged to hold the pair of lower side rail members in laterally spaced relation to one another.
Other objects, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims.